theres a few good motel/b&b type things near gare du nord, the eurostar station in paris. When i last stayed there like last year it was 45 euro per night for me and my gf, which isnt too bad. only problem is the area around the station is a bit scummy...... you could try out wiki travel for some good, cheap accomodation ideas?While in Paris, I highly recommend taking a river boat cruise along the seine... its absolutely beautiful, especially in the early evening.Sorry I couldnt be of more help!

Just for anybody reading this thread in the future, you wouldn't really want to stay near the Eurostar stop if you can help it. The Eurostar goes to Gare de Norde station and it isn't exactly the safest area of Paris.